The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2000-353006 filed on Nov. 20, 2000 and Japanese Patent Application No. 2001-016383 filed on Jan. 24, 2001 the entire contents thereof are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an air pressure detecting device for a wheel for detecting the air pressure of a tire to allow the driver to recognize the air pressure of the tire even while the vehicle is being operated.
2. Description of Background Art
One air pressure detecting device for a wheel for allowing the driver to recognize the air pressure of a tire even while the vehicle is being operated is disclosed in Japanese Patent Laid-open No. Hei 10-44726 entitled xe2x80x9cTire Air Pressure Warning Device.xe2x80x9d
According to FIG. 1 of Japanese Patent Laid-open No. Hei 10-44726, the disclosed arrangement is a tire air pressure warning device that includes a valve stem 10 (the reference numeral is from the publication) mounted on a wheel rim 1. A case 2 is disposed beneath the valve stem 10 and a transmitter 7 is housed in the case 2. A pressure detector 3 is provided together with a signal processing circuit 4 and a cell 5.
While the above tire air pressure warning device is of a structure that can be mounted on a tubeless tire, it is not suitable for use on a tire with a tube.
In order to use the tire air pressure warning device on a tire with a tube, it is necessary to attach the transmitter 7 to the tire tube. However, the transmitter 7 cannot directly be attached to the tire tube.
It is therefore an object of the present invention to provide an air pressure detecting device for a wheel which can be mounted on a tire with a tube.
To achieve the above object, an air pressure detecting device according to the present invention is provided for detecting the air pressure of a wheel of a vehicle which has a tire tube disposed in a tire. The air pressure detecting device is disposed between the tire tube and the rim of the wheel for detecting the air pressure of the tire wherein the air pressure detecting device includes an annular seat mounted in an opening defined in the tire tube, a lid member held in removably fitting engagement with the seat, and a detecting and transmitting unit integrally mounted in the lid member for detecting an air pressure in the tire tube and transmitting pressure information out of the detecting and transmitting unit.
The air pressure of the tire which is detected is effective based on driving information for detecting the air pressure while the vehicle is being operated. The annular seat is mounted in the opening defined in the tire tube, the lid member is removably fitted over the seat, and the detecting and transmitting unit is integrally mounted in the lid member for detecting an air pressure in the tire tube and transmitting pressure information out of the detecting and transmitting unit for the driver to know the air pressure of the tire while the vehicle is being operated.
The detecting and transmitting unit is integrally mounted in the lid member, and the lid member is held in removably fitting engagement with the seat. When the tire is to be replaced, the lid member is removed, and the detecting and transmitting unit is attached to a new tire for use.
Thus, the detecting and transmitting unit can be reinstalled for reuse. As a result, the air pressure detecting device can effectively be used for material saving.
According to the present invention, the air pressure detecting device is characterized in that an air valve is integrally mounted on the lid member for introducing air into the tire tube.
With the air valve integrally mounted on the lid member, the number of parts of the wheel is reduced. As a result, the costs of the wheel and the air pressure detecting device are lowered.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.